Boring-bit.



W. POTTER.

BORING BIT.

APPLICATION FILED SEPT. 22, 1910.

1,004,902, Patented Oct. 3, 1911.

5 vw Moz /zam Fotter UNITED STATES PATENT OFFICE.

WILLIAM POTTER, OF NEW YORK, N. Y.

BORING-BIT.

To all whom it may concern.-

Be it known that I, VVILLIAM POTTER, a citizen of the United States of America, and residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Boring-Bits, of which the following is a specification, such as will enable those skilled in the art to which it appertains to make and use the same.

This invent-ion relates to boring bits, being an improvement over that shown and described in my application for Letters Patent of the United States filed July 19, 1910, Serial Number 57 2,721, and the object thereof is to provide, in bits provided with posi tive, self-contained, means for holding the same to the work, additional means for producing a smooth bore, both at the surface of the material being bored and throughout the length of said bore.

A further object is to provide such a bit which is very rapid in operation for the reason that the pitch thereof may be materially increased, over the pitch of the centering and holding screw now employed, due to the holding means previously referred to and which are more positive, irrespective of the pitch thereof, than the comparatively minute threads on the usual centering screws of bits now employed.

A further object is to provide, in bits of this type, inclined cutting edges in order that a sliding out will occur instead of the breast cut of the usual bits and whereby great ease of operation results.

A further object is to perform the smoothing of the bore after the operation of the said holding means and at approximately the same time as the chip lifting cutter or cutters, thus loosening the said chip from the bore at the moment of lifting, or nearly so, whereby comparatively little force is required to remove the said chips from the material being bored and thus assisting in the ease of operation; and a still further object is to provide such a bit which is not only positive and easy of operation, but which performs its function without the necessity of inward force on the part of the operator, which is very simple in construction, easily resharpened, and comparatively inexpensive.

My invention is fully set forth in the following specification, of which the accom- Specification of Letters Patent.

Application filed September 22, 1910.

Patented Oct. 3, 1911.

Serial No. 583,189.

panying drawings form a part, in which the separate parts are designated by the same reference characters in each of the views, and in which Figure 1 is a view of one side of a boring bit constructed according to my invention; Fig. 2 is a face view of the operative end; and Fig. 3 is a fragmentary View similar to Fig. 1, but showing the opposite side thereof.

In the drawings forming a part of this application I have shown a boring bit comprising the usual, or any desired, shank a and spiral flange (62, at the outer end of which are arranged the cutting members and a centering screw also used to feed the bit into the material, but it will be observed that I greatly increase the pitch of the threads of said screw over those now employed and thus reduce the number of said threads, and, if desired, I may dispense with the said screw for certain uses as hereinafter pointed out.

In the form of embodiment shown in the drawings I provide three cutting edges, Z), 0 and (Z, the former of which is at the forward end of a spiral groove 02 formed by a spiral lip b which is a gradually enlarged cont-innation of the thread of the screw a and whereby a spiral rib is formed in the material being bored between the said lip and the lower end of the flange (4 thus preventing the withdrawal of the bit by upward force and compelling constant feeding of the bit in its rotation into the material, the cutting edge I) being solely for this purpose.

The cutting edge a is, as shown, upon the lower end of the flange a and arranged a full spiral turn above the edge 6, the function thereof being to separate the spiral rib formed by the edge Z) from the material by passing thereunder adjacent the wall of the bore being formed and thus lifting the detached rib for removal by means of the flange a in the usual manner.

The cutting edge (Z is arranged longitudinally of the hit, upon the flange (H, at a point approximately diametrically opposite the cutting edges 6 and 0 and extends a short distance below the edge 0 but not to the edge Z), the function of this cutter (Z being to form the wall of the bore smoothly by separating the rib of material previously referred to from the wall of the bore at about the moment of operation of the cutting edge a but at an appreciable period after the operation of the edge I), the sole function of the cutter (Z being, as stated, that of smoothing the wall of the bore.

It will thus be seen that, once the bit is started in the material, nothingmore than rotary force is needed because of the fact that the lip 2 is beneath the rib being spirally formed in the material, and a full turn behind the said rib formation the rib lifting cutter becomes operative as well as the cutter removing the rib from the wall of the bore, both of the first two cutters being inclined in order to effect a sliding or drawing cut for ease of operation and, by reference to Fig. 1 it will be seen that the groove 6 is gradually widened rearwardly of the cutting edge 6 thus preventing friction of the rib formed in the material therein, also for ease of operation.

For special uses the screw a may be dis pensed with, in which event a cut is made in the material by a chisel or the like whereby the bit may be started, but the cuttingedges are unchanged in such use and, when once started, my bit will feed itself automatically without any downward force on the part of the operator and in the desired direction, this not being true of bits as usually constructed under all conditions.

In Figs. 1 and 3 I have shown two lines 00 and :0 the former indicating the surface of the material being bored at the moment of rib formation by the cutting edge Z) and the latter indicating the said surface at the moment of operation of the cutting edge 0, as well as of the edge (Z, the said lines also showing the relative posit-ions of the said cutting edges.

It will be obvious that I may increase the number of the individual cutting edges, preferably by duplicating them as in bits at .present employed, thereby balancing the operation thereof, but this is not essential to a proper operation as will be understood, and various other changes in and modifications of the details shown and described may be made, within the scope of the following claims, without departing from the spirit of my invention or sacrificing its ad vantages.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is 2-- 1. A boring bit provided with a centering screw, the thread of which is continued to form a spirally arranged cutter of slightly less diameter than said bit, a floor cutter adjacent the inner edge of said spiral cutter, and a wall cutter so located as to operate after said spiral cutter and previous to said floor cutter, and in cooperation with the latter.

2. A boring bit provided with. a centering screw having a steep pitch permitting a strongly defined thread which is continued to form a cutter of slightly less diameter than said bit, a forwardly directed Wall cutter on a plane approximately that of the termination of the spiral cutter, and a floor cutter arranged slightly above said wall cutter, whereby the operation of the latter occurs between the operations of the spiral cutter and the floor cutter.

In testimony that I claim the foregoing as my invention I have signed my name in presence of the subscribing witnesses this 21st day of September, 1910.

IVILLIAM POTTER.

Vitnesses R. J. SLANDOR F, J. C. LARSEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

